Self-cleaning oven door structure

ABSTRACT

An oven door of sheet metal construction having an outer door panel, an inner door liner and an inner panel that is adapted to be exposed to the internal oven temperatures. The inner panel is of shallow pan configuration with a peripheral flange that extends into a large opening in the inner door liner. A strip of gasket material encircles the inner panel and spaces the inner panel from the inner door liner in the manner of a thermal break. An insulation guard closes the inner panel to form a closed boxlike structure that is substantially filled with thermal insulating material. A cooling air channel is located between the insulation guard and the outer door panel so that currents of cooling air may pass up through the cooling channel.

United States Patent 1191 White 1451 June 5, 1973 [54] SELF-CLEANINGOVENDOOR 3,453,997 7/1969 Klepzig ..126/198 STRUCTURE 3,561,423 2/1971Holtkamp ..126/198 Inventor: James A. White, Louisville, Ky.

General Electric Louisville, Ky.

Filed: Sept. 5, 1972 Appl. No.: 286,450

Assignee: Company,

, References Cited UNITED STATES PATENTS lO/l967 8/1968 6/1969 [57]ABSTRACT An oven door of sheet metal construction having an outer doorpanel, an inner door liner and an inner panel that is adapted to beexposed to the internal oven temperatures. The inner panel is of shallowpan configuration with a peripheral flange that extends into a largeopening in the inner door liner. A strip of gasket material encirclesthe inner panel and spaces the inner panel from the inner door liner inthe manner of a thermal break. An insulation guard closes the innerpanel to form a closed box-like structure that is substantially filledwith thermal insulating material. A cooling air channel is locatedbetween the insulation guard and the outer door panel so that currentsof cooling air may pass up through the cooling channel.

5 Claims, Z'Drawing Figures PATENTEDJuu 5197s FIGJ BACKGROUND OF THEINVENTION A pyrolytic self-cleaning oven operates at oven temperaturesas high as 950 F. as is described in the basic U.S. Pat. of Bohdan HurkoNo. 3,121,158, which is assigned to the same assignee as is the presentinvention. Safety regulations of Underwriters Laboratories, Inc. arebecoming more strict each year regarding the allowable surfacetemperatures present on the outer surface of the oven door during theself-cleaning operation. Therefore it is encumbent upon rangemanufacturers to continuously refine and improve their door designs tosatisfy the needs of the range user. The door of a self-cleaning ovenmust be locked during the entire high temperature cycle; accordingly, itis important that the door be of high strength capability so that itwill not warp and allow large amounts of the heat to escape from theoven nor allow the entrance of large amounts of air into the oven whichcould cause backfires to occur. Hence it is'necessary to design a rigiddoor of sheet metal construction to lessen the weight which at the sametime will be rigid enough to function almost as a solid door. This dooris' designed to offer excellent thermal isolation of the inner panelfrom the remainder of the door, while there is afforded high doorstrength even though the inner panel is mounted in such a way that it isallowed to expand and contract during the high temperature operationwith a minimum of crazing of the porcelain enamel finish on the innerpanel.

The principle object of the present invention is to provide an oven.door of sheet metal construction with high strength capability while atthe same time having a reliable thermal break between an inner panel andthe inner door liner which allows thermal expansion and contraction ofthe inner panel.

A further object of the present invention is to provide an oven door ofthe class described for use with a high temperature self-cleaning ovenwherein an inner panel is supported in an opening in an inner door linerin such a way that the inner panel is allowed to expand and contractduring the change of temperature within the oven without putting unduestresses or strains on the panel and on the porcelain enamel finish thatis applied to the exposed surface thereof.

A further object of the present invention is to provide an oven door ofthe class described with an insulation guard that cooperates with theinner panel in such a way as to produce a box-like structure that isadapted to be filled by thermal insulating material to form a rigidstructure with good thermal insulating characteristics. Y

SUMMARY-OF THE INVENTION The present invention, in accordance with oneform thereof, relates to an insulated door construction for a hightemperature oven where the door has an outer panel and an inner doorliner that in turn supports an inner panel that projects into the ovenand is exposed to the internal oven temperatures. The inner door linerhas a large opening and the inner panel has a peripheral flange thatjust slips into the opening. A strip of gasket material encircles theperipheral flange of the inner panel and serves as a thermal breakbetween the inner panel and the inner door liner. Fastening means extendthrough the peripheral flange and gasket material into the inner doorliner. An insulation guard closes the inner panel to form a closedbox-like structure that is substantially filled with thermal insulatingmaterial. A cooling air channel is located between the insulation guardand the outer door panel so that currents of cooling air may pass upthrough the cooling channel.

BRIEF DESCRIPTION OF THE DRAWINGS This invention will be betterunderstood from the following description taken in conjunction with theac companying drawings and its scope will be pointed out in the appendedclaims.

FIG. 1 is a perspective view of a free-standing domestic range having anoven door embodying the present invention, where the door is shown inits horizontal, fully opened position.

FIG. 2 is a cross sectional elevational view on an enlarged scalethrough the center of the door to show the general nature of the doorconstruction.

DESCRIPTION OF THE PREFERRED EMBODIMENT Turning now to a considerationof the drawings and in particular to FIG. 1, there is shown forillustrative purposes a free-standing electric range 10 having a topcooling surface 11 with a plurality of surface heating elements 12, abaking oven 13 formed by a box-like oven liner 14 and a front-openingaccess door 16. Of course, this door invention is not limited to a usein electric free-standing ranges. The oven could be heated by gas, itcould be a built-in wall oven or any other type of high temperatureheated cavity. The oven cavity 13 is supplied with two standard heatingelements; namely, a lower baking element 18 and an upper broilingelement 19 located adjacent the top wall of the oven liner. The backedge of the cooking surface 11 is supplied with a backsplash 21 whichsupports a control panel including multiple selector switches 22 for thesurface heating elements 12, and an oven selector switch 24, an oventhermostat" control 26 and finally an oven timer 28 for timing both thecooking operations as well as the oven cleaning cycles. Positionedbeneath the oven 13 is a pull-out drawer 30 which is a storage drawerfor cooking utensils and the like. However, in most gas ovens, thislower space is alloted to a broiler compartment.

The oven door 16 is hinged to the range body along the bottom edge ofthe door by means of counterbalanced hinge levers 32 such as are shownin the patent of G.R. Sherman, U.S. Pat. No. No. 2,873,737, which isassigned to the same assignee as is the present invention. An oven doorlatch handle 15 is shown at the front edge of the cooktop 11 formanipulation of a latch mechanism located beneath the cooktop forengaging the oven door 16 when it is in a closed position and locking itshut during the entire oven cleaning cycle. A suitable oven latchmechanism is shown in the patent of J. S. Fox, U.S. PatfNo. 3,367,697 ofthe present assignee. I

As is best seen in FIG. 2, the oven door 16 is of generally sheet metalconstruction having three main elements; an outer door panel 34, aninner door liner 36, and an inner panel 38 that is supported from theinner door liner. The outer door panel 34 is of shallow panconfiguration by virtue of the fact that it has a slight rearwardlyfacing peripheral flange 41. The inner door liner 36 is also of shallowpan configuration, and it is edge of the door, while at the bottom ofthe door there is a tab and slot connecting relationship at 45 alongmost of the bottom edge of the door which prevents separation of theouter door panel from the inner door liner unless the screw fasteners atthe top of the door are first removed.

The inner door liner 36 includes a generally rectangular outwardembossment 47 which is adapted to project somewhat into a recessed frontframe 49 of the oven body. Notice the boxl-like oven liner 14 has anoutwardly turned front flange 51 which bears against the front frame 49because the oven liner is pulled rearwardly into the oven body bytension means (not shown) such as J-bolts or the like as is standardpractice in this art.

The inner panel 38 is of shallow pan shape with a front facingperipheral flange 55, and this inner panel is adapted to project intothe throat of the oven liner 14 in the manner of a close fitting plug.The flat face of the embossment 47 of the inner door liner 36 is formedwith a large opening or cut-out for accommodatingthe flanged portion 55of the inner panel 38 therein, thereby substantially filling theopening. This opening is also provided with an inwardly turned, frontfacing peripheral flange 57 which closely parallels the peripheralflange 55 of the inner panel 38. This peripheral flange 55 of the innerpanel is shown provided with an inner step 59 that extends completelyaround the inner panel so that the inner panel is of the correct size tofit within the throat of the oven liner l4. Wrapped around theperipheral flange 55 near the edge thereof is a strip gasket 61 ofthermal insulating material such as woven fiberglass or the like. Thisgasket 61 has an enlarged exposed edge 62 that is adapted to sealagainst the front flange 51 of the oven liner when the door 16 isclosed. The strip gasket 61 is sandwiched between the flange 55 and thegenerally parallel flange 57 of the inner door liner 36. Fasteningscrews 63 are threaded from inside the inner panel 38 and extend throughthe flange 55, the gasket 61 and the flange 57. There would probably bea minimum of two screws 63 on each side of the panel and possibly threeon the top and bottom edges, but the number of such screws is notcritical. However, it is well to realize that this type of inner panelconstruction and assembly allows for the expansion and contraction ofthe inner panel during the high temperature cycle as the strip gasket 61almost serves as a somewhat resilient mounting means.

A sheet metal insulation guard 67 is provided to close the interior ofthe inner panel 38. This insulation guard happens to be assembled to aninwardly facing flange 69 of the peripheral flange 57 of the inner doorliner 36 as by means of screws 71, as this is the best means ofthermally isolating the inner panel 38 from the remainder of themetallic parts of the door 16. However, a modification would be to mountthe insulation guard 67 from the other peripheral flange 55. By closingoff the inner panel 38, this insulation guard 67 forms a strong box-likestructure which goes far towards reinforcing the door into a very rigidstructure. The interior of this box-like structure is substantiallyfilled with thermal insulating material 75 of fiberglass or the like soas to retain much of the heat generated within the oven cavity and allowas little heat loss as possible.

Another expedient for holding down the surface temperature of the frontface of the oven door is to provide natural convection air coolingwithin the door by creating air inlet openings 77 along the bottom edgeof the I rearwardly facing flange 41 of the outer door panel 34,

as well as air outlet openings 79 in the top edge of the outer doorpanel 34. There is an air channel provided by the spacing of theinsulation guard 67 back away from the outer door panel 34, thus thiscooling air is able to pick up some of the heat stored in the thermalinsulation and insulation guard 67 and serve somewhat as a heatexchanger to remove a portion of this heat by carrying it back into thekitchen. This air flow is primarily useful during the high temperatureselfcleaning cycle although it also functions during normal coolingoperation which makes for cool cooking as far as the outer temperatureof the oven door 16 is concerned.

Modifications of this invention will occur to those skilled in this art;therefore, it is to be understood that this invention is not limited tothe particularembodiments disclosed, but that it is intended to coverall modifications and equivalents which are within the true spirit andscope of this invention as claimed.

What is claimed as new and is desired to be secured by Letters Patent ofthe United States is:

1. An oven door comprising an outer door panel, an inner door liner andan inner panel all fastened together, the outer door panel having arearwardly facing peripheral flange, said inner door liner having afront facing peripheral flange telescoped with the flange of the outerdoor panel, the inner door liner having a generally rectangular outerembossment, and fastening means for holding the inner door liner to theouter door panel, the inner panel being slightly smaller in size thansaid embossment and having a front facing peripheral flange whichextends into a large opening in the embossment, said opening also havinga peripheral flange generally parallel to the said flange of the innerpanel, and a strip of thermal gasket material sandwiched between theperipheral flange of the inner panel and the peripheral flange of thelarge opening in the inner door liner, and a limited number of fasteningmeans holding the two last mentioned flanges and the gasket together,said gasket also having an enlarged exposed edge encircling the innerpanel and adapted to seal against an adjoining surface of an oven in themanner of a door sealing gasket, and an insulation guard within the'doorattached to at least one of the inner panel flanges and the flange ofthe opening in the inner door liner to form a shallow box-like structureof high rigidity, and thermal insulation within this box structure, acooling air char nel in the door between the insulation guard and theouter door panel with air inlet means along the bottom portion of thedoor and air outlet means along the top portion of the door so thatcurrents of cool air may pass up through the cooling channel.

2. An oven door of sheet metal construction comprising an outer doorpanel, a spaced inner door liner and an inner panel that is adapted tobe exposed to the high temperatures within the oven, and fastening meansfor holding the inner door liner and the outer door panel together, theinner panel being smaller in size than the inner door liner and having aperipheral flange, the inner door liner having a large opening forreceiving at least a portion of the peripheral flange of the inner paneltherein, a strip of thermally insulating gasket material encircling theperipheral flange of the inner panel, the large opening in the innerdoor liner having a peripheral flange around the edge of the openingthat closely parallels the peripheral flange of the inner panel, and aplurality of widely spaced fastening means joining the two peripheralflanges with the gasket being sandwiched therebetween, said gasket alsohaving an enlarged exposed edge encircling the inner panel and adaptedto seal against an adjoining surface of an oven in the manner of a doorsealing gasket whereby the door gasket serves as a thermal break betweenthe inner panel and the remainder of the metallic door parts, thermalinsulation within the door for retarding the conduction of heattherethrough, and an insulation guard of sheet form within the doorsupported from at least one of the said peripheral flanges to form withthe inner panel a closed box structure, the said thermal insulationsubstantially filling this box structure.

3. An oven door as recited in claim 2 wherein there is a cooling airchannel formed in the door between the said insulation guard and theouter door panel with air inlet means along the bottom portion of thedoor and air outlet means along the top portion of the door so thatcurrents of cool air may pass up through the cooling channel.

4. An oven door of sheet metal construction comprising an outer doorpanel, an inner door liner and an inner panel, the outer door panelbeing of shallow pan configuration with a rearwardly facing peripheralflange, the inner door liner also being of shallow pan configurationwith a front facing peripheral that telescopes with respect to the outerdoor panel flange, and fastening means for holding the outer door paneland the inner door liner together, the inner door liner having an outerembossment on its inner face with a large opening formed therein, thesaid inner panel being of shallow pan configuration with a front facingperipheral flange that is encircled by a strip of thermally insulatinggasket material and fits within the said large opening, said gasketstrip having an enlarged exposed edge adapted to seal against anadjoining surface of an oven in the manner of a door sealing gasket, andfastening means between the inner panel flange and the inner door linerwhereby the door gasket serves as a thermal break between the innerpanel and the remainder of the metallic door parts, and an insulationguard within the door supported from the inner door liner and closingthe interior of the inner panel to form a closed box-like structure, andthermal insulation material substantially filling the said boxstructure.

5. An oven door as recited in claim 4 wherein the said large opening inthe inner door liner has a front facing peripheral flange generallyparalleling the peripheral flange of the inner panel, the said fasteningmeans between the inner door liner and the inner panel being connectedbetween the peripheral flanges of these two members.

1. An oven door comprising an outer door panel, an inner door liner and an inner panel all fastened together, the outer door panel having a rearwardly facing peripheral flange, said inner door liner having a front facing peripheral flange telescoped with the flange of the outer door panel, the inner door liner having a generally rectangular outer embossment, and fastening means for holding the inner door liner to the outer door panel, the inner panel being slightly smaller in size than said embossment and having a front facing peripheral flange which extends into a large opening in the embossment, said opening also having a peripheral flange generally parallel to the said flange of the inner panel, and a strip of thermal gasket material sandwiched between the peripheral flange of the inner panel and the peripheral flange of the large opening in the inner door liner, and a limited number of fastening means holding the two last mentioned flanges and the gasket together, said gasket also having an enlarged exposed edge encircling the inner panel and adapted to seal against an adjoining surface of an oven in the manner of a door sealing gasket, and an insulation guard within the door attached to at least one of the inner panel flanges and the flange of the opening in the inner door liner to form a shallow box-like structure of high rigidity, and thermal insulation within this box structure, a cooling air channel in the door between the insulation guard and the outer door panel with air inlet means along the bottom portion of the door and air outlet means along the top portion of the door so that currents of cool air may pass up through the cooling channel.
 2. An oven door of sheet metal construction comprising an outer door panel, a spaced inner door liner and an inner panel that is adapted to be exposed to the high temperatures within the oven, and fastening means for holding the inner door liner and the outer door panel together, the inner panel being smaller in size than the inner door liner and having a peripheral flange, the inner door liner having a large opening for receiving at least a portion of the peripheral flange of the inner panel therein, a strip of thermally insulating gasket material encircling the peripheral flange of the inner panel, the large opening in the inner door liner having a peripheral flange around the edge of the opening that closely parallels the peripheral flange of the inner panel, and a plurality of widely spaced fastening means joining the two peripheral flanges with the gasket being sandwiched therebetween, said gasket also having an enlarged exposed edge encircling the inner panel and adapted to seal against an adjoining surface of an oven in the manner of a door sealing gasket whereby the door gasket serves as a thermal break between the inner panel and the remainder of the metallic door parts, thermal insulation within the door for retarding the conduction of heat therethrough, and an insulation guard of sHeet form within the door supported from at least one of the said peripheral flanges to form with the inner panel a closed box structure, the said thermal insulation substantially filling this box structure.
 3. An oven door as recited in claim 2 wherein there is a cooling air channel formed in the door between the said insulation guard and the outer door panel with air inlet means along the bottom portion of the door and air outlet means along the top portion of the door so that currents of cool air may pass up through the cooling channel.
 4. An oven door of sheet metal construction comprising an outer door panel, an inner door liner and an inner panel, the outer door panel being of shallow pan configuration with a rearwardly facing peripheral flange, the inner door liner also being of shallow pan configuration with a front facing peripheral that telescopes with respect to the outer door panel flange, and fastening means for holding the outer door panel and the inner door liner together, the inner door liner having an outer embossment on its inner face with a large opening formed therein, the said inner panel being of shallow pan configuration with a front facing peripheral flange that is encircled by a strip of thermally insulating gasket material and fits within the said large opening, said gasket strip having an enlarged exposed edge adapted to seal against an adjoining surface of an oven in the manner of a door sealing gasket, and fastening means between the inner panel flange and the inner door liner whereby the door gasket serves as a thermal break between the inner panel and the remainder of the metallic door parts, and an insulation guard within the door supported from the inner door liner and closing the interior of the inner panel to form a closed box-like structure, and thermal insulation material substantially filling the said box structure.
 5. An oven door as recited in claim 4 wherein the said large opening in the inner door liner has a front facing peripheral flange generally paralleling the peripheral flange of the inner panel, the said fastening means between the inner door liner and the inner panel being connected between the peripheral flanges of these two members. 